1.

If `int_(0)^(prop)(3x^(2)+2x+1)dx=14`, then `prop = …….`A. 1B. 2C. `-1`D. `-2`

Answer» We have `int_(0)^(alpha) (3x^(2) + 2x +1)dx = 14`
`rArr " "[(3x^(3))/(3)+(2x^(2))/(2) +x]_(0)^(alpha) = 14`
`rArr" " [x^(3) + x^(2) + x ]_(0)^(alpha) = 14`
`rArr" "alpha^(3) + alpha^(2) + alpha - 0 = 14`
`rArr" "alpha^(3) + alpha^(2) + alpha - 14 = 0`
Let `alpha= 2`, then
`(2)^(3) +(2)^(2) +2- 14 =0`
So, `alpha = 2` satisfies above above equation.
Hence, the correct answer form the given alternative is (b)


Discussion

No Comment Found

Related InterviewSolutions